and I would call this a bug, because why do we have a model class system with associations, if we aren't able to save a complete object graph? And the scenario to always make a step-by-step saving (first save the store of the association, then save the root object) isn't the best saving method, isn't it?
If you have complex object graphs you have to ensure you are sending the complete graph to the server, so it saves this object transactionally to the the database - if we don't do this we have to skip our ORM and have to deal with foreign key problems and so on...

Really, this should be possible from within the framework. Otherwise, there's really no use using associations; it's probably less painful then to add another store and link everything manually. Is this planned for any near future releases?